CCK-8 (a peptide having the structure Asp-Tyr(SO.sub.3 H)-Met-Gly-Trp-Met-Asp-Phe-NH.sub.2) is known to have feeding inhibition properties see for example J. E. Morley, Minireview: `The ascent of cholecystokinin--from gut to brain`, Life Sciences, Vol. 30 (6), pp. 479-493, 1982!.
A number of synthetic peptides having feeding inhibition properties are known, for example those disclosed in European Patent Applications 226217 and 268297. The peptides of the present invention differ from these in having an optionally sulphated hydroxyphenylacetic acid group at the N-terminal.